We wish to investigate the supportive structures of teeth in an attempt to clarify the relatinship between anatomy and physiological function. The mechanical characteristics of tooth supportive tissue will be quantitated by measuring the mechanical input impedance of teeth in human and animal subject in vivo. The method (used previously by the principal investigator) involves virbrating the teeth with an electro- magnetic driver at various frequencies and measuring the resultant motion with an accelerometer. We intend to extend the frequency range of the previous measurments (60-5000 Hz.) downward to .001 Hz. After establishing baseline data for normal human subjects, we will test various animals in order to find a suitable animal model for further experimentation whose nature would preclude the use of humans. Experiments on animals will be designed to test the validity of mechanical equivalent circuits derived from the impedance data. The effects on mechanical impedance of various periodontapathies will be evaluated and, from the equivalent circuit model, suitable treatment will be suggested. Patients selected from the dental clinic will be treated accordingly and the mechanical impedance of the involved teeth will be followed. We expect to find that measurements of mechanical impedance at certain frequencies will indicate the relative state of the health of the several tooth supportive tissues. Our ultimate objective is to design clinical instruments and procedures suitable for measuring the relative health or degree of dysfunction of these tissues. Malfunction of these support structures can lead to tooth loss and/or be indicative of systemic disease.